double request aftar form submission

hi, i got a problem if toast is set to loader in ```root.tsx``` file there is double request after submit

## example code
```javascript
export function action() {
return redirectWithToast('/sign-in', { message: 'User created successfully', type: 'success' }, {
status: 201,
})
}

export default function SignUp() {
return (

Test

)
}
```

Start with root.tsx and the action/Form example in the issue, reproducing the submission with the toast set to loader. Trace the redirectWithToast flow and request handling to identify why submission results in two requests. Done means the example submits once while retaining the intended toast behavior; no test file is mentioned.

Written by the indexing model from the issue text.